OBJECTIVE: To investigate the effect of cordyceps sinensis (CS) extract and losartan (Los) on the expression of Klotho (Kl), P53, P21, and apoptosis in renal tubular epithelial cell NRK-52E induced by angiotensin II (Ang II), and to elucidate its therapeutical mechanism in Ang II induced renal tubular epithelial cell apoptosis. METHODS: NRK-52E cells were incubated with CS with or without Ang II for 24 hours. Experimental groups were divided according to the increasing concentrations of CS:0 (serving as controls), 5, 10, 20, 40, and 80 mg/L. The optimal concentration of CS was selected and cells were divided into 5 groups: controls, Ang II (1*10(-8) mol/L), Ang II (1*10(-8) mol/L)+CS (40 mg/L), Ang II (1*10(-8) mol/L)+Los (1*10(-5) mol/L), and Ang II (1*10(-8) mol/L)+CS (40 mg/L)+Los (1*10(-5) mol/L). After 24 hours, cell proliferation was evaluated by MTT assay. The mRNA and protein expression of Kl, P53 and P21 were measured by RT-PCR. Activity of caspase-3 was evaluated by caspase-3 activity assay Kit. Cell apoptosis was determined by Annexin V-FITC/PI double staining and flow cytometry. RESULTS: Certain concentrations of CS promoted the proliferation of NRK-52E cells and increased cells proliferation inhibited by Ang II (P<0.01 or P<0.05 ). Ang II significantly down-regulated the mRNA and protein expression of Kl, and up-regulated the levels of P53 and P21. Caspase-3 activity and apoptotic rates were decreased, too (all P values<0.01). CS or/and Los significantly increased the expression of Kl mRNA and protein down-regulated by Ang II, decreased P53 mRNA and protein expression, P21 mRNA and protein expression,and inhibited caspase-3 activity and apoptotic rates(all P values<0.05). No cooperative effects were observed in the two drugs (P>0.05). CONCLUSION CS can increase the expression of Kl down-regulated by Ang II, decrease P53 and P21 expression and caspase-3 activity, and reduce Ang II induced NRK-52E cell apoptosis, which may be part of its mechanism of the protective effects on hypertensive renal damage.
Angiotensin II ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Cells, Cultured ; Cordyceps ; chemistry ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Epithelial Cells ; cytology ; metabolism ; Glucuronidase ; genetics ; metabolism ; Humans ; Kidney Tubules ; cytology ; metabolism ; Losartan ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism